In order to achieve augmentation of the accuracy in calculation of
noise and augmentation of the accuracy in a
noise check which is performed, for example, when an
electronic circuit is designed and further realize significant reduction of the time required for a
noise check and augmentation of the operation efficiency by reduction of the man-hours of a designer in a noise analysis, a noise checking apparatus includes a model production section (3) for producing a
simulation model of a circuit portion relating to a noticed wiring line, a
simulation section (4) for performing a
simulation using the simulation model to calculate a
signal waveform which propagates in the noticed wiring line and calculate a noise waveform superposed on the
signal waveform for each kind of noise, a noise waveform synthesis section (5) for synthesizing the
signal waveform and the noise waveforms with generation timings of the noise waveforms taken into consideration to obtain a noise composite waveform, and a noise checking section (6) for performing noise checking based on the noise composite waveform.